Detectives said a clerk working at Joyeria El Mercadito was working alone Friday when a man came in armed with a gun.
The suspect started breaking display cases and scooping up jewelry and ran off.
The clerk wasn't hurt, but police haven't been able to find the suspect.
If you have any information that could help investigators find the robber, you're urged to call Ventura police Crime Stoppers at (800) 222-TIPS or (800) 222-8477.
